题解 | 查找在职员工自入职以来的薪水涨幅情况

SELECT
    t1.emp_no,
    (t1.salary - t2.salary) AS growth
FROM
    (
        SELECT
            emp_no,
            salary
        FROM
            salaries
        WHERE
            to_date = '9999-01-01'
    ) as t1
    JOIN (
        SELECT
            e.emp_no,
            s.salary
        FROM
            employees e
            JOIN salaries s ON e.emp_no = s.emp_no
            AND e.hire_date = s.from_date
    ) as t2 ON t1.emp_no = t2.emp_no
ORDER BY
    growth;